Technical Abstract:
Alternative egg production methods are becoming more popular with US consumers. As the drive to expand the retail shell egg market to accommodate consumer shifts proceeds, a need arises for additional information to ensure processing methodologies result in safe eggs from all egg sources. A study was conducted to determine if there were differences in the prevalence of Salmonella, Listeria, and Campylobacter on and within eggs and in the environment of a sister flock of conventional cage and free range laying hens. Microbial sampling occurred approximately every six weeks between 20-79 wks of age. There was a significantly greater (P < 0.0001) prevalence of Campylobacter present in the free range nest boxes (NBS) compared to free range grass (FRG) and conventional cage swab (CS) samples (number of positives: 8 NBS; 1 FRG; 0 CS). Seven isolates of Listeria innocua were detected with no significant difference in prevalence between the treatments. Isolates were associated with egg shells (2 free range floor; 1 cage) and the free range environment (2 NBS; 2 FRG). There were twenty-one Salmonella isolates detected between all sample locations. There was no significant difference in the prevalence of Salmonella detection between the treatments. Additional studies are needed to fully understand the impact of alternative production methods on the prevalence of pathogens in nest run eggs.